Standardization of the Experimental Model ofHaemophilus ducreyiInfection in Human Subjects

Abstract

Human volunteers were challenged with Haemophilus ducreyi. Twenty subjects were inoculated with 2 doses (approximately 30 cfu) of live and 1 dose of heat-killed bacteria at 3 sites on the arm. Eight subjects were assigned to biopsy 1 or 4 days after inoculation, and 12 were biopsied after they developed a painful pustular lesion or were followed until disease resolved. Papules developed at 95% of 40 sites infected with live bacteria (95% confidence interval [CI], 83. 1%-99.4%). In 24 sites followed to end point, 27% of the papules resolved, 69% (95% CI, 47.1%-86.6%) evolved into pustules, and 4% remained at the papular stage. Recovery rates of H. ducreyi from surface cultures ranged from 13% to 41%. H. ducreyi was recovered from biopsies of 12 of 15 pustules and 1 of 7 papules, suggesting that H. ducreyi replicates between the papular and pustular stages of disease.

Haemophilus ducreyi-Induced Interleukin-10 Promotes a Mixed M1 and M2 Activation Program in Human Macrophages

“…Informed consent was obtained in compliance with the human experimental guidelines of the U.S. Department of Health and Human Services and the Institutional Review Board of Indiana University. Enrollment and exclusion criteria, preparation of H. ducreyi, and inoculation procedures were reported previously (2).…”

Evaluation of an Isogenic Major Outer Membrane Protein-Deficient Mutant in the Human Model of Haemophilus ducreyi Infection

“…Inoculation of approximately 55 (95% CI, 34.9 to 75.3) and 100 (95% CI, 55 to 144) CFU results in pustule formation rates of approximately 70 and 90%, respectively (2). Previous studies have shown that disease outcome (papule, pustule, or resolution) at each site in an individual subject inoculated at multiple sites with identical suspensions of bacteria is independent (3,31). Therefore, in parent-mutant comparisons, subjects are inoculated with multiple doses of the parent and mutant, and site rather than subject is used as the unit of analysis.…”

Evolution of the Cutaneous Immune Response to Experimental Haemophilus ducreyi Infection and Its Relevance to HIV-1 Acquisition

“…Biopsies designated CS were obtained from seven subjects who participated in a previous human challenge trial (15,18). Tissue specimens for FACS analysis were obtained from 10 volunteers (189 and 195-204) who were infected for the purposes of this study, 2 subjects who participated in a mutant parent trial (186 and 190) (33), and 2 subjects (164RR and 172RR) who participated in a reinfection trial (Table I).…”

“…The enrollment procedures, exclusion criteria, preparation of the bacteria, and inoculation procedures for the human challenge experiments are described in detail elsewhere (13)(14)(15). Each volunteer was inoculated at two or three sites on the upper arm with live H. ducreyi 35000HP (a human passaged isolate of 35000) and at one site with heat-killed 35000HP.…”

“…To characterize the immune response to H. ducreyi infection and study the pathogenesis of chancroid, we developed a human model of experimental infection that closely mimics the papular and pustular stages of natural chancroid (13)(14)(15). In the model, the bacteria are delivered to the epidermis and dermis on the upper arm with an allergy testing device.…”